Well apparatus



M. R. JONES WELL APPARATUS May 2, 1967 2 Sheets-Sheet l Filed Nov. 20,1964 IIIIIl JM H. m V m May 2, 1967 M. R. JONES 3,316,984

WELL APPARATUS Filed Nov. 20, 1964 2 Sheets-Sheet B Marv/f7 draf/@5 lNVENTOR.

ATTO/PNE VJ United States Patent Texas Fiied Nov. 20, 1964, Ser. No.412,758 6 Claims. (Cl. 175-7) This invention relates generally toapparatus for use in drilling and/or completing an oil or gas well at anunderwater level. More particularly, it relates to apparatus of thistype having an improved system for guiding drilling and/vor completionequipment between a vessel at water level and the wellhead to which suchequipment is adapted to be connected.

For example, in the drilling of a well of this type, a blowout preventeris lowered and connected onto the upper end of a casiiig head iixed to abase at the underwater level, whereby pressure control may be maintainedover the well as the various casings are lowered into the `well throughthe head. Upon completion of the drilling operation, the blowoutpreventer is removed and replaced by a .so-called Christmas tree whichconnects to the head to maintain control over the well during itsproduction.

In either case, some means must lbe provided for guiding such equipmentbetween a vessel at the water level and the casing head, so that it maybe lowered onto the head for connection thereto and raised tfrom thehead and back to the vessel upon disconnection therefrom. It has beenproposed to so guide drilling equipment through tubes having their lowerends sunk into the underwater level or otherwise lixed with respectthereto. However, these tubes are obviously unsuited for use in thegreat depths and turbulent wave conditions encountered in the drillingand completion of many modern offshore oil and gas wells. That is, theyare so large as to impose excessive lateral loads on the wellhead andvessel between which they are connected.

For this reason, the industry has turned to a system for guiding suchequipment which includes a pair of flexible cables anchored at theirlower ends to the base of the casing head for extension upwardly to thevessel and collars or sleeves on the equipment providing followers forsliding vertically along the cables. One problem with this type ofsystem is the necessity of threading and unthreading the cables throughthe followers of different equipment to be lowered and raised. This isnot only a diliicult and time consuming operation, but also requiresthat the guide cables extend upwardly to at least the level orf thevessel and thus into the area of maximum wave action. More particularly,in operation, the cables are maintained taut by connection of theirupper ends in some way to the vessel, as by means of a winch, whichmakes it diiiicult to remove the vessel from and return it to the guidesystem. Still further, in the event the cable kinks or bends, it maybecome impossible to move the follower over it in raising or loweringthe equipment.

` An object of this invention is to provide a guide system of thegeneral type above described which obviates the aforenoted shortcomings.

A more particular object is to provide such a system which is notsusceptible to the large lateral loadings of the tubular type system,and which at the same time does not require threading or other intricateoperations involved in the use of the flexible cable and follower typesystem.

Another object is to provide a guide system of this type which is ofsuch construction that its upper end may be disposed beneath the moresevere wave action.

A Lturther object is to provide a guide system of this type from whichthe vessel may be removed and to which fice the vessel may be returnedwith a minimum of preparation.

These and other objects are accomplished, in accordance with theillustrated embodiments of the invention, by a guide system in which atleast three cables having their lower ends connected to the wellheadextend upwardly therefrom toward the water level in circumferentiallyspaced apart relation. The cables are held taut and thus vertically by ameans at the upper ends, which preferably comprises one or more oats ata level beneath the vessel, so as to form a vertical passage throughwhich the equipment may ybe lowered and raised. There is a rigid frameon the equipment which slides along and within the cables to guide itwithin the passage, and rigid bands connect the cables at verticallyspaced levels to form a cage in which the cables are prevented frombeing spread apart a sufficient distance to permit the equipment to passtherethrough.

Since this system is just as open as the cable and follower typeheretofore rused, it is just as free from lateral loadings. At the `sametime, since` the equipment is merely constrained within the verticalpassage within them, there is no need to thread the cables through theguide frame on the equipment. Furthermore, the upper end ost' the cageformed by the cables and bands need not be connected to the vessel andmay, as above noted, be held taut merely by tioats at a level beneaththe vessel. Thus, in operation, the equipment to be lowered from thevessel need only be stabbed into the upper end of the cage.`

In the drawings, wherein like reference characters are used throughoutto designate like parts:

FIG. l is an elevational view of a guide system constructed inaccordance with one embodiment of the presa ent invention for `use inraising and lowering equipment between an underwater wellhead at itslower end and a vessel at water level above its yupper end;

FIG. 2 is an enlarged perspective view of part of the guide system ofFIG. l and illustrating the sliding engagement of the guide frame on theequipment with respect to the cables of the cage.

FIG. 3 is a cross sectional view of the system of FIGS. l and 2, as seenalong broken line 3 3 of FIG. 1;

FIG. 4 is another cross sectional view of the guide systems of FIGS. land 2, as seen along broken line 4-4 of FIG. 1; and

FIG. 5 is a perspective view of part of a guide system constructed inaccordance with another embodiment of the present invention, andillustrating the equipment carried by the guide frame just prior to itsbeing lowered onto the upper end of the wellhead to which the lower endof the guide cables are connected.

With reference now to the details of the above described drawings, -andparticularly the embodiment of the invention shown in FIGS, l to- 4, acasing head 10 is shown in FIG. l to extend upwardly from a base 11 onthe upper end of conductor casing 12. As well known `in the art, theconductor casing extends downwardly into a well bore drilled at theunderwater level 13, and the casing and base are anchored to such levelin a suitable manner.

During the drilling of this underwater well, additional strings ofcasing are lowered through and landed within the casing head 10. Forthis purpose, and as also shown in FIG. 1, there is a vessel 14 at thewater level 15 from which such casing may be lowered into the well.Thus, a

. derrick 16 and the usual hoisting apparatus (not shown) are mountedabove an opening 17 through the vessel so as to position in at leastapproximate alignment with the axis of the well during the drilling andcompletion procedure.

In order to maintain pressure control over the well during the drillingprocedure, a blowout preventer 18 is lowered on a pipe 19 from thevessel 14 onto the upper end of the casing head 1l). More particularly,a device 20 is carried on the lower end of the preventer 18 for remoteconnection to a neck 21 about the upper end of casing head 10. Thisconnecting device and the neck on the casing head may be constructed asshown generally in U.S. Patent No. 3,096,999, and modified in such amanner as to permit it to be actuated by suitable apparatus on thevessel at water level. As well known in the art, the preventer and itsconnector provide continuations of the bore through the tubing head sothat the various strings of casing may be lowered through them and intothe casing head.

The embodiment of the guide system of the present invention shown inFIGS. l to 4, includes six circumferentially spaced apart exible cables22 connected at their lower ends to the base 11 by means of anchors 23.These cables are interconnected at vertically spaced apart levels bymeans of triangularly shaped rigid bands 24 which are welded orotherwise secured to the outer sides of the cables so as to provide theabove described cage. Floats 25 are connected about the uppermost band24 so as to hold the cables taut and thus vertically disposed. As shownin FIG. 1, the oats 25 are disposed beneath the vessel 14, and thus asubstantial distance beneath the water level 15, so that they aresubject to a minimum of wave action.

A triangularly shaped guide frame 26 is connected about the blowoutpreventer 18 by means of struts 27 or the like for guidably movingvertically within the cage formed by the interconnected cables 22 andbands 24.

More particularly, the frame 26 is symmetrical to each of the bands 24,and has outer dimensions somewhat smaller than the inner dimensions ofeach of the bands 24 so that its outer sides slide along the guidecables. This non-circular shape of the guide frame 26 and bands orientthe equipment being lowered about its vertical axis, so that suchequipment may be connected onto the casing head in a desired rotationalposition with respect thereto.

As previously noted, the bands 24 cooperate with the floats 25 inpreventing the cables 22 from being spread apart a distance sucient topermit the guide frame 26 to move between any adjacent pair of them.Thus, the spacing of the bands vertically along the length of the cagedepends on the number and normal spacing between ,the interconnectedcables as well as the tension in the cables.

As shown in FIG. 1, there is a funnel 28 connected to the uppermost band24 and diverging upwardly from its lower end to facilitate the operatorin stabbing the guide frame 26 into the uppermost end of the cage. Thisfunnel may include `an upper enlarged rigid band 29 connected to theuppermost band 24 of the cage by means of downwardly and inwardlyconverging rigid legs 30. It of course extends upwardly to a levelrelatively close to the bottom of the vessel 14 so as to perform itsintended function.

This cage may be Iinstalled into the position shown in FIG. l in anumber of ways. For example, the lower ends of the cables 22 may beconnected to the anchors 23 for lowering with the base 11. To facilitatethis, the floats may be made heavier when lowered with the upper end ofthe cage and then made lighter to hold the cables with the desiredtension.

Upon installation of the apparatus illustrated and described above inconnection with FIG. 1, the blowout preventer 18 and frame 24 arelowered on pipe 19 through the funnel 28 `and into the upper end of thecage. As the frame is guided downwardly through the cage, connector 2l)is lowered onto the neck 21 about casing head 10, and hydraulic controlsare then actuated to cause the locking parts of the connector to fastenonto the neck. The pipe 19 is then backed otf from the blowout preventerand raised from within the cage of the guide system, and the casingstrings are lowered through the guide system and into the casing head inthe drilling procedure.

Obviously, upon completion of the drilling process, this same guidesystem may be used in lowering a Christmas tree onto the wellhead. Ineither case, the vessel 14 may be moved away from the well site withouthaving to be disconnected from the guide system. Conversely, the vesselneed only be moved back into the position of FIG. 1 in order to continuethe drilling and/ or completion of the well. Y

In many respects, the guide system illustrated in part in FIG. 5 issimilar to the system illustrated and described in FIGS. l to 4. Thus,it includes at least three circu-mferentially spaced apart flexiblecables 31 connected at their lower ends to a base about casing head 10for extension upwardly therefrom. As shown in FIG. 5, there are foursuch cables generally equally spaced apart and `interconnected atvertically spaced apart levels by means of rigid bands 33. The upper endof the cage formed by the interconnected cables and bands is providedwith oats and preferably a funnel similar to those shown in FIG. 1 so asto hold the ables taut and facilitate stabbing of equipment into thecage.

In this embodiment of this invention, each of the bands 33 is ofcircular configuration in a section taken perpendicular to the axis ofthe well and the cage. The guide frame 34 connected to the blowoutpreventer :18 or other equipment to be guidably raised and/or loweredwith respect to the casing head 10 is similarly shaped and of somewhatlesser outside `dimensions than the in side dimensions of the bands 33.Thus, the outer circular side of the guide frame 34 moves slidably alongthe inner side of the cables 31 which are, in turn, welded or otherwisesecured a-t their outer sides to the inner sides of the bands 33.

As in the case of the guide system shown in' 'FIGS'. 1 to 4, this latterguide system enables equipment such as the blowout preventer 18 to belowered into a posiy tion for connection -to the casing head 10 by meansof a device 20 carried beneath the blowout preventer and having lockingparts for connecting about the neck 21 on the upper end of the casinghead. Also, of course, the spacing between adjacent bands 33 is dictatedby the number and spacing of `the cables as well as the tension in thecables, whereby adjacent cables are kept from being spread apa-rt adistance which would permit the guide frame 34 to move between them.

Inasmuch as the guide frame and guiding sufaces of the cage arecircular, they will not in and of themselves lorient the equipment aboutits vertical axis. Thus, in order to permit the equipment to beconnected to the' casing head 10` in a desired rotational sense, thereis a camming ring 35 on the wellhead with which a cor- `respondinglyshaped camming ring 36 connected on the guide frame 34 is adapted tocooperate. As shown in FIG. 5, the cam ring 35 is supported above acircular frame 32 connected to the casing head with its upper' camming`surface in an angularly disposed position with respect to the axis ofthe well and cage of the guide systern. Similarly, the cam `ring `36 iscarried beneath the guide frame 34 by means of one or more vertical rods`37 extending down from the lower side of the guide frame 34 to disposeits lower camming surface `at substantially the same angle.

As the connector 20 approaches a landed position on the neck 21 of thecasing 'head 10i, the lower surface on cam ring 36 will engage with theupper surface on cam ring 35 so as to orient `the equipment into thedesired position. That is, the mere weight of the equipment will causethe upper cam ring 36 to turn about its axis until its lower surface isdisposed parallel to the upper surface of cam ring 35. This embodimentis preferred over that shown in FIGS. 1 to 4 since it does not requirethat the operator lower the guide trarne into the cage in anypredetermined relationship 'about a vertical axis.-

As in the case of the guide system shown in FIGS. 1 to 4, the systemshown in FIG. 5 may also be used in raising and lowering a Christmastree with respect to the wellhead during the completion process.Inasmuch as the system functions in the same manner as that shown anddescribed in connection with FIG. 4, this procedure need not beexplained again.

From the foregoing, it will be `seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forth,together with other advantages which are obvious and which are inherentto the apparatus.

It will be unders-tood that certain features and subcombinations are ofutility and may be employed with- ;out reference to other features andsubcombinations. This is contemplated `by and is within the scope of theclaims.

As many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying d-rawings is to beinterpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

`1. In a system for guiding equipment between water level and a wellheadat an underwater level, at least three flexible cables having theirlower ends connectable to the wellhead for extension upwardly therefromin circumferentially spaced apart relation, means on the upper ends ofthe cables for holding them taut, and rigid bands connecting the cables.a-t vertically spaced apart levels.

2. In a system for use in drilling and/ or completing an underwaterwell, a wellhead at the underwater level, at lest three exible guidecables having their lower ends connected to the wellhead incircumferentialy spaced apart relation, rigid bands connecting thecables at spaced apart vertical levels between their upper and lowerends, and means on the upper ends of the cables holding them taut so asto provide a vertically disposed passage through which equipment may bepassed between water level and said wellhead.

3. A system for guiding equipment between a vessel `at water level and awellhead located at an underwater level, comprising at least threecircumferentially spaced Aapart llexible cables extendable verticallyupwardly from said wellhead .toward a vessel at the water level, a rigidframe connectable about the equipment for sliding along and with thecables to guide the equipment for vertical passage Ibetween said vesseland said wellhead, and rigid bands connecting the cables at spaced apartvertical levels to maintain the cables sufficiently close together toprevent said frame from passing between any two of them.

y4. A system of the character defined in claim y3, wherein said framehas a non-circular portion slidable along said cables so as to maintainit in a predetermined rotational position during such passage.

5. A system for use in drilling `and/or completing a well at anunderwater level, comprising a wellhead at the underwater level, -atleast three circumferentially spaced apar-t flexible cables extendingvertically upwardly from said well-head toward a vessel at water level,rigid 4bands connecting the cables at spaced .apart vertical levels, andequipment adapted for connection to the wellhead and having rigid guidemeans thereabout for sliding along and within the cables between saidvessel and said wellhead.

6. A system of the character defined in claim 5, wherein said guidemeans and said wellhead have means providing cam surfaces for orientingsaid equipment into a desired rotational position with respect to thewellhead as it is lowered onto the wellhead.

References Cited by the Examiner UNITED STATES PATENTS 987,266 3/1911Smith 175--9 1,175,725 y3/1916 Dunbar 175-10 3,015,360 '1/1962 Stratton175-7 X 3,017,934 1/1962 -Rhodes et al. 175-7 X 3,111,692 11/1963 COX175-8 X 3,177,954 4/1965 Rand 175--7 3,209,827 10/ 1965 Lacy et al.175-7 X ERNEST R. PURSER, Primary Examiner.

CHARLES E. OCONNELL, Examiner.

R. FAVREAU, Assistant Examiner.

1. IN A SYSTEM FOR GUIDING EQUIPMENT BETWEEN WATER LEVEL AND A WELLHEADAT AN UNDERWATER LEVEL, AT LEAST THREE FLEXIBLE CABLES HAVING THEIRLOWER ENDS CONNECTABLE TO THE WELLHEAD FOR EXTENSION UPWARDLY THEREFROMIN CIRCUMFERENTIALLY SPACED APART RELATION, MEANS ON THE UPPER ENDS OFTHE CABLES FOR HOLDING THEM TAUT, AND RIGID BANDS CONNECTING THE CABLESAT VERTICALLY SPACED APART LEVELS.